Apparatus for hermetic closure of filled containers

ABSTRACT

The present invention relates to a method of and an apparatus for hermetic closure of filled containers of the kind made of foil or sheet material and having an opening surrounded by a marginal flange, with a cover made of foil or sheet material for closing the opening by getting sealed on the container along its flange.

United States Patent 1 1111 3,908,334

Rychiger 1 Sept. 30, 1975 [541 APPARATUS FOR HERMETIC CLOSURE 3.020.6862/1962 Rueckert et a1. 53/1 12 A X OF FILLED CONTAINERS 3.340.668 9/1967Bofinger 53/112 R X 3.353.325 11/1967 Jensen et a1. 53/112 A X [75]Inventor: Hans Rychiger, Bern, Switzerland [73] Assignce: Alupak AG,Bern, Switzerland Primary E.\uminer-Travis S. McGehee [22] Filed: Sept.18, 1973 [21] Appl. No.: 398,544

[30] Foreign Application Priority Data Sept. 20 1972 Switzerland13717/72 [52] US. Cl 53/86; 53/112 R; 53/296 [51] Int. Cl. B65B 31/02[58] Field of Search 53/22 R, 86, 112 R, 112 A, 53/296 [561 ReferencesCited UNITED STATES PATENTS 2.825.194 3/1958 Page .1 53/296 X Atlorner,Agent, or Firm'Michael S. Striker [57] ABSTRACT The present inventionrelates to a method of and an apparatus for hermetic closure of filledcontainers of the kind made of foil or sheet material and having anopening surrounded by a marginal flange. with a cover made of foil orsheet material for closing the opening by getting sealed on thecontainer along its flange.

4 Claims, 2 Drawing Figures APPARATUS FOR HERMETIC CLOSURE F FILLEDCONTAINERS Particularly for containing and for the purpose of sellingsingle consumer rations of liquid food, milk, cream, jam, etc.,preferably one way containers are used, being made of foil or sheetmaterial and closed with a tear-off cover. However, often whentearing-off the cover a portion of liquid content is spouted out of suchcontainers. It has been found that this disadvantage can be avoided ifthe closed container has a reduced inside pressure.

It is an object of the present invention to reduce the inside pressurein such containers before they are hermetically sealed. 7

The method according to this invention achieves such object in thattools for punching out the cover and for sealing it on the container areused to enclose the open container in a hollow space which will behermetically closed from outside air at the latest after the cover ispunched out and disposed in the hollow space, and in that pressure willbe reduced in the closed hollow space below the outside atmosphericpressure while the cover is placed upon and sealed to the containerflange in order to hermetically close the container opening.

The apparatus according the invention for carrying out this methodcomprises upper and lower tools for punching out the cover and forplacing and maintaining the container and cover in registering positionfor the purpose of and during the sealing operation. This apparatus ischaracterised in that a lower tool is surrounded at its circumference bya pushing element determined for effecting the punching stroke of thefemale collar of the punching tools, whereby this pushing element andthis female collar have each an annular surface for mutual tight contactand hermetically enclose together with the other tools during thepunching stroke a hollow space wherein the container and cover arelocated, which space is connected to an air suction duct traversing thelower tool and is closed from outside air at the latest after the coveris punched out and until the container is sealed.

The container which has been scaled by following the method according tothe present invention has a cover which is inwardly cambered due toreduced inside pressure.

The invention will now be described, by way of example, with referenceto the accompanying drawing, in which:

FIG. 1 shows a schematic vertical section through that part of theapparatus which comprises the tools for punching out the cover and forsealing the same on the container, and

FIG. 2 shows the hermetically closed container in vertical section.

Referring to FIG. 1, on a traverse l of the frame 2 of the apparatus isrigidly mounted an upper punching tool 3 having a plan face correspondsto the shape of the cover to be punched out. A female punching tool 4 isarranged below the tool 3 for cooperating therewith in punching out thecover from a sheet or strip 5 of foil material which gets stepwiseconveyed between the punching tools 3 and 4. By not illustratedoperating means the tool 4 can be lifted and lowered with respect to thetool 3 and traverse 1 for executing the punching stroke, whereby anaxially displaceable ring-plate 6 surrounding the tool 3 is pressed fromabove upon the strip 5 and the female tool 4 by pressure springs 6awhich are disposed between the traverse l and the ringplate 6. An airsuction duct 7 traverses vertically the upper tool 3 and leads via acontrol valve 8 into a vacuum supply tank 9.

The apparatus comprises in its lower portion a lower two-part toolconsisting of a cup-like sealing tool 10 located in a heating body 11which tightly contacts the tool 10 laterally and from below. The heatingbody is mounted on a traverse 12 that is vertically movable in the frame2 of the apparatus by the operation of not illustrated driving means.'The other part of the lower tool is a bearing plate 13 for carrying thecontainer 14 to be sealed. This plate is located in the cup of thesealing tool 10 and has on the bottom side a rod with cylinder 15 bywhich it is vertically guided in the traverse 12 for relative movementwith respect to the sealing tool 10. The bearing plate 13 has radialgrooves 16 in its top side and is vertically penetrated by an airsuction duct 17 leading through the rod and cylinder 15 over a controlvalve 18 into the above cited vacuum supply tank The heating body 11' isprovided with bore holes 19 for the installation of heating elements,i.e., of electric resistance heaters. A thermally insulating ring 20 isinterposed between the heating body and the traverse 12, while thelatter can be cooled by water or another cooling agent flowing throughthe holes 21 provided in the traverse 12. On the top side of the heatingbody ll'is mounted a push ring-plate 22 surrounding the sealing tool 10on its circumference. This push ring plate 22 has a plane top surface 23determined to abut against the plain bottom surface 24 of the femalepunching tool 4 for effecting the punching stroke when the lower tool10, 11 is lifted. Thereby the two plane surfaces are adapted to achievea tight annular contact.

The operation of the described apparatus and the method of sealing thefilled container are as follows:

At the beginning of the working cycle, the bearing plate 13 is about ina lift position as shown in FIG. 1, while the lower tool 10, 11 has beenlowered with its upper sealing edge 25 located closely below the topsurface of the plate 13 in order to permit that a filled container 14can be pushed upon this plate. Thereafter, the lower tool 10, 11 islifted, abuts with its sealing edge 25 against the marginal flange 26 ofthe container 14 and raises the same from the plate 13. The lift of thetool 10, ll continues, whereby it reaches with the push ring 22 thefemale punching tool 4 and raises the same, so that the strip 5 will beclamped between the tool 4 and the ring-plate 6. Then the punching outof the cover 27 from the strip 5 takes place.

The container 14 and the cover 27 are now in a hollow space which hasbeen tightly closed from the outside air since immediately before thebeginning of the punching operation, under cooperation of the strip 5and thereafter solely by means of the parts 11 and 22 of the lower tool,the female tool 4 and the upper tool 3.

By opening the control valve 8 shortly before the end of the punchingoperation the cover 27 gets locked to the tool 3 by pressure reductionin the suction duct 7.

Then, by opening the control valve 18, the pressure gets also reduced inthe hollow space through the suction duct 17 and the bores 28 in thesealing tool 10. Meanwhile, the heating sealing tool 10 has raised thecontainer 14 with its marginal flange 26 against the locked cover 27 andeffects the sealing operation whereby the container is closedhermetically along the flange. The valves 8 and 18 will be closed andthe tool 10, l1 and the female tool 4 together with the ringplate 6 willbe lowered into their initial position, whereupon the plate 13 projectsslightly above the sealing edge 25 and the closed container 14, 27 canbe removed from the plate, while the strip is advanced by one step.

Since within the closed container is there is subatmospheric pressure,the cover 27 is inwardly cambered, as is shown in FIG. 2. The airsuction duct 7 through the upper tool 3 is not imperatively needed.Immediately before punching out the cover, the hollow space in cludingthe container will be hermetically closed and gets then evacuated by thesuction duct 17. Also at the end of the punching operation the reducedpressure in the hollow space will be maintained, since the punchingtools immediately read their overlapping positions.

What I claim is:

1. An apparatus for sealing an opening of a filled sheet-materialcontainer in a manner to prevent spurt ing of the container contentsduring the later breaking of the seal, comprising a lower punching toolfor punching a closure from a sheet of closure material; an upwardlyopen cupped receiver for accommodating a filled sheet-material containerhaving an upwardly facing opening; cooperating juxtaposed sealingsurfaces on said lower punching tool and said receiver which engage oneanother when said receiver is moved upwardly against said lower punchingtool so that the latter forms with said receiver an enclosed chamber inwhich the container is located; pressure-reducing means for producing insaid chamber and said container a sub-atmospheric pressure; an upperpunching tool above and cooperating with said lower punching tool topunch said closure when said chamber and container are at saidsub-atmospheric pressure; and sealing means for sealing the punchedclosure to said container over said opening thereof.

2. An apparatus as defined in claim 1. wherein said pressure-reducingmeans comprises a suction duct penetrating said receiver andcommunicating with the interior thereof.

3. An apparatus as defined in claim 2, and further comprising means forholding the punched closure on one of said punching tools by suctionuntil said chamber is at said sub-atmospheric pressure.

4. An apparatus as defined in claim 2, said container having a flangewhich surrounds said opening and to which said closure is to be sealed;and wherein said receiver has a sealing edge projecting upwardly forengagement with said flange; said sealing means comprising heating meansfor heating said sealing edge to effect a heat-seal between said closureand said flange.

1. An apparatus for sealing an opening of a filled sheetmaterialcontainer in a manner to prevent spurting of the container contentsduring the later breaking of the seal, comprising a lower punching toolfor punching a closure from a sheet of closure material; an upwardlyopen cupped receiver for accommodating a filled sheet-material containerhaving an upwardly facing opening; cooperating juxtaposed sealingsurfaces on said lower punching tool and said receiver which engage oneanother when said receiver is moved upwardly against said lower punchingtool so that the latter forms with said receiver an enclosed chamber inwhich the container is located; pressurereducing means for producing insaid chamber and said container a sub-atmospheric pressure; an upperpunching tool above and cooperating with said lower punching tool topunch said closure when said chamber and container are at saidsub-atmospheric pressure; and sealing means for sealing the punchedclosure to said container over said opening thereof.
 2. An apparatus asdefined in claim 1, wherein said pressure-reducing means comprises asuction duct penetrating said receiver and communicating with theinterior thereof.
 3. An apparatus as defined in claim 2, and furthercomprising means for holding the punched closure on one of said punchingtools by suction until said chamber is at said sub-atmospheric pressure.4. An apparatus as defined in claim 2, said container having a flangewhich surrounds said opening and to which said closure is to be sealed;and wherein said receiver has a sealing edge projecting upwardly forengagement with said flange; said sealing means comprising heating meansfor heating said sealing edge to effect a heat-seal between said closureand said flange.